The present invention relates to a device for tilting sewing machine hooks to facilitate the threading operation.
In addition to the normal upper sewing elements, conventional sewing machines which sew one or more parallel chain-stitched seams are also provided with one or more hooks which are displaced in a longitudinal movement at right angles to the direction of advancement of the article being sewn and in a transversal movement parallel to the direction of advancement.
In the case of multi-needle chain-stitch sewing machines, the number of hooks corresponds to the number of needles and they can be disposed either parallel to the direction of advancement or transversally thereto.
In the case of the known types of multi-needle sewing machines, considerable difficulty has been experienced in threading the hooks, either because the latter, for reasons of space, are completely or partially concealed by other parts of the machine or because they are disposed side by side in a position which is not easily accessible to the operator.
This difficulty is most aggravated in sewing machines provided with four needles, wherein one of the most commonly employed hook arrangements is that known as the "tandem" arrangement in which the hooks are mounted side by side in pairs and in two separate planes on a shaft pivoting about its own axis and which are disposed transversally relative to the direction of advancement of the article being sewn.
With conventional four needle sewing machines having the tandem hook arrangement, considerable difficulty has been experienced in threading the hooks, particularly the rear hooks, as they are practically concealed by the front hooks.
A considerable amount of time is lost in threading the hooks which results in what is considered a substantial loss in production with this type of sewing machine.
To simplify respresentation thereof, and for purpose of brevity specific reference will only be made hereinafter to a machine having two hooks.